London is the starting point for a number of motorway routes. The M25 is an orbital motorway which enables vehicles to avoid travelling through central London and is one of the busiest motorways in Europe.

Like the other stations Charles Holden designed for the extension, Arnos Grove was built in a modern European style using brick, glass and reinforced concrete and basic geometric shapes. A circular drum-like ticket hall of brick and glass panels rises from a low single storey structure and is capped by a flat concrete roof. The design was inspired by Gunnar Asplund's design of the Stockholm City Library.

The centre of the ticket hall is occupied by a disused ticket office (a passimeter in London Underground parlance) which houses an exhibition on the station and the line. Like Holden's other stations on the extension, Arnos Grove is a Grade II listed building. The building features as one of the 12 "Great Modern Buildings" profiled in The Guardian during October 2007 and was summarised by architectural critic Jonathan Glancey as "...truly what German art historians would describe as a gesamtkunstwerk, a total and entire work of art."

Through his leadership of the MR, SER and MS&LR, Watkin had the amibtion to construct a new mainline railway connecting the north of England, via London and Kent to the continent. Although his plans for a channel tunnel to be constructed by his Anglo-French Submarine Railway were never realised, the MS&LR constructed its London extension in the 1890s from Annesley, Nottinghamshire to the MR's station at Quainton Road in Buckinghamshire to a continental loading gauge. Reflecting its enhanced connections the MS&LR changed its name to the Great Central Railway in 1987.

To encourage tourist day-trips on the MR, Watkin planned a pleasure grounds at Wembley Park, with a large tower, "Watkin's Tower", intended to be larger than the Eiffel Tower. The park opened in 1896, but because of cost and structural problems, the tower was never completed and was demolished after Watkin's death. The site was subsequently used for Wembley Stadium.